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Questions tagged [hvac]

(Heating, Ventilating, and Air Conditioning) For questions about installing, repairing, and troubleshooting HVAC systems.

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18 views

Dedicated 240v 30A Circuit Switched for A/C and NEMA 14-30

I have a dedicated 240 volt circuit that's hard wired into my air conditioning unit. The circuit has a 30 amp breaker at the main box and another 30 amp breaker on the wall next to my air conditioner....
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1answer
16 views

How do I determine where to connect a new C wire inside my furnace when no control panel or wiring terminal exists?

I am replacing my existing thermostat with a new smart thermostat that requires a C wire connection and the old unit did not. I intended to utilize the unused Blue wire which is not connected on ...
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0answers
15 views

air handler not turning on

Assume an ac compressor doesn't work. Will the air handler still come on if the thermostat is set to fan "on"? Does this differ system to system? I am trying to troubleshoot a non-responsive ac ...
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2answers
85 views

How do I deaden the sound of water dripping on metal?

I live in a two story apartment complex (upstairs neighbors are REAL nice). My bedroom has an AC Box/Swamp Cooler mounted into the wall. Directly above it is a similar unit for my neighbors. The ...
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1answer
65 views

Best air conditioner for cold blasts?

The old air conditioners I had could blow out snow literally that is how cold they got, now air conditions are only moderately cold. What would be the best system to get to just blast one giant vent ...
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1answer
48 views

Why is my AC only blowing out Ice cold air and freezing over AC lines?

I've had a company come out and tell me the ac and furnace are ran from 2 different fans and they recharged the AC unit. However, prior to this the AC was still freezing over the lines. If I have the ...
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45 views

Wand or 2 foot long stick between my master bath fan and outdoor flood lights connecting to share wiring for power?

I'm divorced. My ex husband had a guy install a junction box on corner of house to spotlight the swing set years ago. Recently I was in the attic and discoved a 2 ft "stick' or "wand' that was quite ...
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1answer
43 views

Line to AC dripping at the furnace

My line from my exterior AC unit is dripping at the furnace. The dripping over time has caused rusting and we've had to replace the control board under it. It appears the root cause of the problem ...
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1answer
56 views

Air Filter size for (new to me) home HVAC

My wife and I just purchased / moved into a new house and I was going through each of the systems and found the HVAC filter, it was literally destroyed (it had filled with crap and crushed itself in ...
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24 views

Rough in bathroom exhaust

So, I have a pretty basic question that I can't really figure out for some reason. Is there a way to rough in bathroom exhaust fans before siding? In other words, there are trim kits for sconces, ...
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0answers
21 views

Side venting range hood through a chimney

After many painful design revisions to update a kitchen built in the 1920s, I think I've finally got it down. One of my challenges has been being stuck with the location of the stove/oven, because ...
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1answer
39 views

Furnace Connect G Wire

I have a dual energy electric/oil furnace that is wired to a thermostat with 2 wires R and W. I don't have any AC. Inside the furnace there is a switch relay to control the fan but it is not connected ...
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2answers
49 views

How to clean a reusable HVAC filter

My HVAC system is around 15 years old and I have a washable air filter. The tech who looked at it last told me to clean the filter out and run water through it once a month. He told me to let the ...
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1answer
40 views

Can I change an orifice to make an R22 evaporator unit compatible with a 410a unit?

I have an R-22 system that was never hooked up or run. It was put in place and then the project was put on hold for several years. The outdoor condenser unit is no longer available obviously. We just ...
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1answer
31 views

Ductless AC Initial Charge

I just purchased an LG mini-split set: 18,000 BTU indoor unit https://www.supplyhouse.com/LG-LSN180HSV5-18000-BTU-Ductless-Standard-Multi-F-Air-Conditioner-Inverter-Heat-Pump-w-Built-In-WiFi-Indoor-...
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1answer
26 views

AC Unit Not Cutting On

My AC unit has the thermostat indoors, a unit in the crawl space and the outdoor unit. Everything was working until I had a contractor come out and add insulation in my crawl space. Now the heat/air ...
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0answers
23 views

Problem connection C wire into Lennox Furnace

I would like to connect my new Honeywell WiFi thermostat (RTH6580WF1001) to a Lennox Elite dual Heater and Cooler system. I don’t have a C wire in my old thermostat. I have read online that I can ...
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1answer
10 views

coleman/york furnace 7 red flashes

My furnace "fails to start" 3 times, then it flashes 7 beeps and quits trying. I can hear it start then the flame "just stops" 3x in a row. What gives?
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1answer
43 views

Flexible round duct - What to use

I'm re-routing some 10x3.25" duct through a bulkhead in my kitchen. Planning to change over to 6" round duct for a 4' segment that is relatively straight (no 90s). It was my intention to use non-...
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0answers
18 views

How can I hot wire my AC unit from my furnace without a hot red wire?

My power control board inside my furnace seems to be broken and a service technician cannot come out until after the memorial day weekend. My thermostat is not receiving power. Using a multimeter I ...
2
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2answers
61 views

Unthreaded holes for AC fan motor mounting screws?

My AC is not working. It is a Trane AC (Model 2TTB0030A1000AA). In the process of diagnosis I tried replacing the capacitor, and that did not help. I tested the fan blades and they no longer spin ...
2
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1answer
38 views

Do any home thermostats have an adjustable control range?

I am having trouble with AC and need to replace it soon ; so I have been listening to it cycle .I knew it only stayed on a short time but I just found it runs less the 2 minutes ; that is with ...
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1answer
51 views

Sealing a closet door that has a gas fired water heater in it

Does anyone know how to make a self sealing door? There's a bedroom in my basement, and it has a door in there that allows you access into the HVAC room (which can be entered from another door in ...
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0answers
27 views

Air conditioner will not shut off

I cannot get my air conditionar to turn off at the thermostate. I turn it to off or auto and it still runs. I have to flip the breaker off to get the unit to turn off. What could be wrong?
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1answer
48 views

Should I insulate metal duct work in basement?

I have a balloon frame house with an unfinished basement. The air handler and furnace are in the basement too. Last fall, we had the duct work removed because it was wrapped in asbestos tape that ...
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1answer
23 views

Replacing A/C thermostat

I think that my mother has a bad thermostat. When the A/C is turned on, the furnace blower works but not the outside unit. However, when I press the contact switch (outside), both the compressor and ...
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1answer
34 views

Two HVAC units on one condensate drain line

I am renting a house with two HVAC units - one upstairs and one downstairs. There were two condensate drain lines (one per unit). The units were older so when they quit working efficiently the ...
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1answer
27 views

Blower Motor Heat and Cool Control Board

I’m an electrician by trade but i have a friend who needed his blower motor replaced. The parts store sold him a motor but it only has one hot leg. The control board has a hot for cooling and a hot ...
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0answers
16 views

Installed Honeywell R8285A 1048 control center combined with a Honeywell PRO 8000 thermostat

to operate an inline duct fan on a long run to a new addition. Thermostat in the new addition activates fan when the thermostat is set to cooling perfectly. I can use it to manually turn on the fan. ...
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0answers
27 views

Where to install C wire?

I need to run new thermostat wire since I don't have a C wire to power my smart thermostat, but need some guidance on where to hook it up. I have five wires at my thermostat, two going back to my ...
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2answers
59 views

I have an unused C wire hooked up to thermostat and have no idea where to connect it to the furnace for power

I know this question gets asked all the time but I've spent hours staring at forums as well as my furnace and at this point I'm desperate. I just bought a nest thermostat that needs a C wire ...
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1answer
42 views

HVAC blower fan won't stop

FINAL UPDATE: I have found the culprit - the Nest thermostat itself. First, I disconnected the t'stat at the control panel and found out that the fan would no longer start upon powering the system. ...
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1answer
32 views

Need to identify wires coming from external AC Unit

idiot DIY'er here :P. I recently installed a smart thermostat and long story short; I removed the two wires from my furnace's board for the external air conditioning unit in the process. I was going ...
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2answers
35 views

a/c doesn't turn on when temperature is reached

I just changed my thermostat and it does the same thing [as the old thermostat did?]. I get up in a.m. thermostat is set at 77 F. When inside room temp reading on the thermostat reaches 77, a/c doesn'...
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1answer
42 views

Cutting 4" hole on Rim Joist

Would it be advisable to cut a 4" hole on the basement rim joist to install a bathroom fan. The joist size is 8" and is supported by a basement wall.
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1answer
49 views

Remove switch that controls thermostat

I recently bought a condominium in a large building, built in 2005. It has a single thermostat, and the thermostat works fine. But right next to the thermostat, there is a switch. It looks like an ...
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1answer
27 views

a/c condensation line not draining

I have a unit that is installed in the attic and is about 2 years old. For the first year everything was fine and then one day it wouldn’t run. So I hooked up the shopvac and sucked the condensation ...
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0answers
14 views

Ac unit blower cuts on off on off

My blower fan cut on off on off on off that fast then it stays on and runs fine. Only dose it at the beginning of the cycle
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0answers
18 views

Name of A/C hose fitting

I have a set of R134A manifold gauges that I would like to use to pull a vacuum on an R410A system. My hoses terminate at the R134A quick connector with the threading on the right of the attached ...
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1answer
24 views

Old furnace with extra wire, but no c terminal Janitrol, 19 year old furnace

I've searched multiple threads regarding this, but I didn't manage to find any that seemed to match my use case. My board doesnt have a C terminal, and it doesn't have the other terminals connect to ...
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0answers
23 views

How do I plug an old duct

While renovating my kitchen, I came across an old exhaust duct in the wall. It goes through the chimney bricks and into the interior of the chimney. The boiler uses a duct within the chimney that is ...
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1answer
46 views

Overflow line tied with Condensate Line

had a house inspection done and the inspector told that Irregular materials were used, I am attaching a pic. how much work is it to repair it? is it a easy fix? Thank you
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1answer
25 views

Can I safely jumper between either G or Y and RC at thermostat panel to troubleshoot AC problem?

I'm trying to troubleshoot a non-functioning AC. The fan does not come on and there is no cool air/condenser does not run. My thermostat is a Braeburn. Three things I'd like to try for ...
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0answers
32 views

AC unit not turning on

My A/C doesn't come on when I set the temperature on the Braeburn thermostat very low. Also, the recirculation fan doesn't come on when I set the thermostats fan setting to 'on', as though the indoor ...
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0answers
30 views

Is this where my HVAC air filter goes?

I moved into a home that was poorly taken care of by the homeowner before. It dawned on me today that I've never replaced the HVAC filter (I guess I'm bad at taking care of the house too :) ) in the ...
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1answer
39 views

Furnace with no “C” connection

I have a mobile home furnace. This furnace only has a 4 wire connection terminal, G,W,R,Y. I also have a condensing unit outside with the 24 volt 2 wires coming to the furnace. I know I connect one to ...
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0answers
38 views

Is one large whole house fan better than two smaller ones?

I'm having an addition put on my house and I'm considering the "Quiet Cool" line of whole house fans. The fans are quite expensive and price wise two small fans are almost the same price as one ...
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5answers
61 views

How to size a whole house fan?

I'm in the middle of a home addition and am thinking about adding a whole house fan. The finished size of the house will be about 2000 square feet - approx 1500 on the main level, and 500 on a lower ...
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0answers
20 views

HoneyWell baseboard thermostat

Hello everyone! Need some help here (trying to help a family member) They recently purchased a home that has a furnace and AC ( with central air) in each room there at these honeywell thermostats. ...
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1answer
35 views

Why doesn't my HVAC system use the away temperature setting?

I have a Carrier Infinity dual-fuel 5 stage HP w furnace. I set the away temp much lower than the home temp but the HP keeps running to bring the temp up to the next home temp. I would think the ...